View Full Version : ISonic 133

3rd April 2007, 11:50 PM
I am thinking of losing my old formula board out of the quiver and going for the IS133 as my biggest board. I have a worry that my mates with formulas will be sailing off into the distance while I'm waiting for the wind to get up.

My big sails are 6.5, 7.8 and 10.3. I presume I will be able to use 7.8 and 6.5 at a push. What about twin cam 10.3, will I need to replace that too?

Does the isonic plane up easily without the need for too much pumping? A few years ago I had a HS105 and whilst it was engaging to sail, its early planing was limited (for a lazy old git, like me)?

6th April 2007, 01:42 PM
Hi Simon,

I own an Is133 and would say that the 7.8 you could use at a push - the 6.5 is too small and there would be no real benefit to putting this sail on the board as by the time you'd use it, you'd not be able to control the (very wide) board anymore. I used mine with a 7m once and decided then that it wasn't what it was made for.

Keep the 10.3 because I have a feeling you will love that on that board. My biggest sail is a full cam 10m and It's brillianty for cruising on light wind days

8th April 2007, 12:37 AM

I guess a key factor is your weight ?

If you're a leightweight like me (65 kg), I fear the iS133 is gonna be a bit of a challenge to ride in 6.5 conditions, especially with severe chop, not because of the width of the board (no problem on my HS105 with 5.4 sail, 26 cm fin, 20-25 knots wind, severe chop and up to 1 m high swell), but because of the shape (sharp and boxy) and thickness of the iS133 rails (thin and rounded on HS105). As challenging as my previous 309 x 70 cm race board with thick/boxy rails, a 6.5 race sail and 40 cm fin...

If you're a medium or heavy weight, I guess 6.5 sail might still be do-able on iS133, not the best combo as compared to HS105, but still OK. I'll leave that to other medium to heavy weight riders to comment further.

WRT planing, especially if you're lazy and heavy, iSonic133 is far superior to HS105 when underpowered, no question. Well to over-powered, the planing difference becomes much less dramatic IMHO (but I'm a lightweight, so I really dunno for medium to heavy weight riders).

WRT your 10.3 sail, I bet it'll be fine on iS133 (no problem with RX2 10.6 sail and 54 cm race fin for me in light winds).

Cheers !


9th April 2007, 06:09 PM
I am 75kg. I'm unlikely to use 6.5 much. i was more worried about the top end 10.3

10th April 2007, 05:47 AM

I've tested iSonic 133 in 7-12 knots of wind with my 10.6 sail. In low wind e.g. 7-9 knots, the 54 cm race fin gives a good grip. The stock 48 cm fin is a bit small in the lightest of puff, but is great overpowered in 10-12 knots. A 44 or 40 cm fin is definitely too small with 10.6 on this board.

In 10-15 knots of wind with a RS2 8.2 sail, the 48 cm fin is perfect underpowered 10-12 knots while a 42-44 cm fin is sweet once overpowered in 13-15 knots of wind (the stock 40 cm fin felt a bit small IMHO).

In 15-20 knots of wind with a RS1 6.6 sail, the stock 40 cm fin is really nice.

In summ with my 65 kg so far :

Early planing : Formula > iS133 ≥ HS105 (well to overpowered) >> HS105 (underpowered)
pointing upwind : Formula > HS105 > iS133 (big fin) >> iS133 (small fin)
comfort/smoothness in chop : HS105 >>iS133 >Formula
jibe in chop : HS105 >iS133 >>Formula
jibe exit speed : iS133 > Formula ≥HS105 (well to overpowered) >>HS105 (underpowered)
speed/control overpowered : HS105 > iS133 >>Formula

So for your 75 kg, I would say go for it if you would use it mainly with your current 7.8 and 10.3 sails. But be warned that both the early planing and pointing upwind/downwind will have nothing in common with your formula. Be prepared to that distinction, this is certainly not a mini-formula (in contrast to HS105 which clearly is).

Cheers !


Erik Loots
13th April 2007, 02:09 AM
For me an Isonic 135 DRAM (we have that one) would work perfect for light wind. I can drive it very good, and it is really fun.

But I am 80kg... and I plane at 9-10 knots when I am really active but normal 11-12 knots. With 7.5 or 8.1 Arrows Maxx speed

My brother (the owner) is 100kg and he surf more passive... he gets away at >15knots so it is not real light wind for him. He likes the Isonic 105 better than Isonic 135... He came off a freeformula 168 and really misses the volume, I said he should buy isonic 135 but it is not a real succes//. But he is going faster... way faster (he did 62kmh (34knots on the isonic 135) And in the past the speeds were about maxxxxxx 30 knots 55kmh.

Isonic vs Formula == Faster vs All the time planing